Field of the Invention
The invention relates to a photosensitive resin composition, and more particularly, to a photosensitive resin composition for color filters.
Description of Related Art
Currently, the color filter is widely used in applications such as color liquid crystal displays, color facsimile machines, and color cameras. With the ever expanding market demand for office equipment such as the color liquid display, the production of the color filter is also technically diversifying. For instance, methods such as the staining method, printing method, electrochemical plating, and dispersion method have all been developed, with the dispersion method currently being the mainstream.
In the process of the dispersion method, a pigment is first dispersed in the photosensitive resin to form a photosensitive resin composition, followed by coating the photosensitive resin composition on a glass substrate. After the steps of exposure and development etc., a specific pattern may be obtained. After repeatedly performing the processes of coating, exposure, and development three times, the desired pixel color patterns of red (R), green (G), and blue (B) may be obtained in the pixel color layer of the color filter. Then, as needed, a protective film may be applied onto the pattern of the pixel color layer.
In the dispersion fabrication process, in the example of the photosensitive resin composition used, (meth)acrylic acid is, for instance, a copolymer polymerized from monomer components, and is used as an alkali-soluble resin of the photosensitive resin composition. Relevant literatures of the photosensitive resin composition are, for instance, Japan Patent Application No. H06-95211, Japan Patent Publication No. H08-183819, and Japan Patent Publication No. H09-311210.
Moreover, in the fabrication process of the color filter, a plurality of heat treatment steps are performed, such as the step of post-bake and the step of forming an ITO film performed individually to, for instance, red (R), green (G), and blue (B) pixel color patterns after forming. The heat treatment steps generally require a temperature of over 200° C. to complete. However, when the known photosensitive resin is heated under the conditions of about 180° C. and 1 hour, problems such as the effect of pigment aggregation particles (the particle diameter of the average pigment aggregation particle is between 1 μm to 10 μm) and poor heat-resistance readily occur in the pixel color layer.
Therefore, by using the polymer of the photosensitive resin composition mentioned in JP 2001-075273, the problems above may be improved, wherein the polymer is obtained from the polymerization of an unsaturated monomer having a carboxyl group and a monomer having a glycidyl group and is used as an alkali-soluble resin for the photosensitive resin composition.
However, with the trend of increasing demand for the color saturation of the liquid crystal display, the proportion of pigments contained in the photosensitive resin composition is also increasing. However, the relative use of the alkali-soluble resin and the photosensitive monomer is decreasing, which causes the crosslinking degree to decrease after exposure. As a result, problems such as the color difference being too large after development and poor develop-resistance occur.
Therefore, satisfying heat-resistance under the premise of limited relative use of alkali-soluble resin and photosensitive monomer and solving the problem of poor develop-resistance are problems that those skilled in the art currently need to solve.